Class 1 hazard sign (the orange lozenge) on a military ammunition load.

HAZMAT Class 1, based on the UNO Hazard Class and Division system, indicates Explosives, which are any substance or article, including a device, which is designed to function by explosion or which, by chemical reaction within itself is able to function in a similar manner even if not designed to function by explosion (unless, in the US, the article is otherwise classed under a provision of 49CFR).

US Army trucks laden with ammunition, displaying the Class 1.1 Explosive placard on the front.

Before shipping an explosive a Special Permit is needed. This permit can only be obtained by the country's Competent Authority. A valid permit is required for each country that the explosive will be shipping to, from, or within. The Competent Authority for the United States is the (US)DOT, Department of Transportation.Department of Transportation